Olivia Munn remembers Shannen Doherty supporting her amid her cancer battle

Olivia Munn shared a special tribute to Shannen Doherty in the wake of the actress' death over the weekend.

While many of Doherty's castmates -- from shows like "Beverly Hills, 90210," "Charmed" and more -- offered up their memories of working with her, Munn opened up about how she was uniquely connected to Doherty through their personal battles with breast cancer.

"I am absolutely heartbroken over the passing of Shannen Doherty," Munn's Instagram post began.

"When I was first diagnosed with breast cancer I remembered how she bravely let the world into her journey and I reached out to her," she continued. "We became instant friends - which I honestly couldn't comprehend at times because watching her on 'Beverly Hills, 90210' was everything to me when I was 10."

Munn said Doherty's character on the '90s teen drama, Brenda Walsh, "is and was and will always be an icon."

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"We bonded through a shared battle and a desire to help other women," she continued.

Munn said Doherty had reached out a few months prior to check in on her, in what would be their last text exchange, saying, "True to form, Shannen was offering her support even though she was in the final stage of fighting this horrific disease."

"Cancer is really f------ scary and Shannen faced it with such dignity, strength and grace. I'm sending all of my love to her mother who was her best friend, hero and champion every step of the way," Munn wrote to end her post. "Fly so high, my friend. 💔💔💔💔."

Doherty first shared she had been diagnosed with breast cancer in 2015.

Munn went public with her diagnosis earlier this year.